that presence of nuclides and heavy metals is linked to the exacerbation of some
microbial diseases in aquatic organisms.
At sufficiently high concentrations, heavy metals are toxic to the organism, and
so, it is important their concentrations to be monitored especially when increased
above the normal levels in the environment before the effects on marine organisms.
The Black Sea drains a surface of land five times larger than its own area, shared
by 17 countries and inhabited by over 160 million people. Rivers, notably the
Danube, Dnieper, Don, Kuban and Bug, bring in about 80% of the pollutants (50%
from the Danube alone). They include agrochemicals, poorly treated industrial
liquid effluents, and domestic wastewater. Atmospheric transport, predominantly
from Europe, and coastal sources, such as direct industrial waste and sewage
discharges or dump sites, account for the remaining 20%. Riverine input of
nutrients, heavy metals, radionuclides, organic compounds and oil is a severe
problem.
The concentrations of rivers pollutants (domestic and industrial discharges)
provide useful information about the sources that have the potential to lead to
local pollution problems along the Black sea coast. The shallow, biologically
productive layer of the Black sea receives water from a waste drainage basin of
about 17 countries. Pollutants, transported by rivers, forms the main source of
pollution in the Black sea.
According to Zaitzev (1992) the estimation of land based sources, the sea
annually receives big amounts of mineral nitrogen, mineral and organic phosphorus, as well oil and oil products, detergents, zinc, lead, mercury, copper, arsenic,
chromium.
Man-made eutrophication of coastal waters and shelf zones has been the most
harmful impact on the sea. The area most affected by eutrophication is the northwestern part of the sea, where the three largest rivers, the Danube, Dniester and
Dnieper are inflowing.
Increase in nutrients in the river discharge triggered the mass development of
phytoplankon and an expansion in the area of its blooms. This phenomenon has
been thoroughly studied by Ukrainian, Romanian and Bulgarian scientists. A large
algal biomass provides good feeding conditions for plant-eating animal plankton
(zooplankton) and a sharp increase in the numbers of some zooplankton species
occurred in the 1970s and 1980s.
Aquatic organisms, especially macroalgae, are widely used as bioindicators for
the study of marine Nuclides and heavy metals are the most harmful elemental
pollutants and are of particular concern because of their toxicities to humans. They
include both essential elements like iron and toxic metals like cadmium and
mercury. Most of them show significant affinity to sulphur and disrupt enzyme
function by forming bonds with sulphur groups in enzymes. Cadmium, copper, lead
and mercury ions bind to the cell membranes hindering the transport processes
through the cell wall. Some of the metalloids, elements on the borderline between
metals and nonmetals, are significant water pollutants (Manahan 1999).
Radionuclides occur naturally in the environment but recently some artificial
radionuclides have been introduced. In the past there have been several accidents, at
18 Radioecology of the Black Sea
297
microbial diseases in aquatic organisms.
At sufficiently high concentrations, heavy metals are toxic to the organism, and
so, it is important their concentrations to be monitored especially when increased
above the normal levels in the environment before the effects on marine organisms.
The Black Sea drains a surface of land five times larger than its own area, shared
by 17 countries and inhabited by over 160 million people. Rivers, notably the
Danube, Dnieper, Don, Kuban and Bug, bring in about 80% of the pollutants (50%
from the Danube alone). They include agrochemicals, poorly treated industrial
liquid effluents, and domestic wastewater. Atmospheric transport, predominantly
from Europe, and coastal sources, such as direct industrial waste and sewage
discharges or dump sites, account for the remaining 20%. Riverine input of
nutrients, heavy metals, radionuclides, organic compounds and oil is a severe
problem.
The concentrations of rivers pollutants (domestic and industrial discharges)
provide useful information about the sources that have the potential to lead to
local pollution problems along the Black sea coast. The shallow, biologically
productive layer of the Black sea receives water from a waste drainage basin of
about 17 countries. Pollutants, transported by rivers, forms the main source of
pollution in the Black sea.
According to Zaitzev (1992) the estimation of land based sources, the sea
annually receives big amounts of mineral nitrogen, mineral and organic phosphorus, as well oil and oil products, detergents, zinc, lead, mercury, copper, arsenic,
chromium.
Man-made eutrophication of coastal waters and shelf zones has been the most
harmful impact on the sea. The area most affected by eutrophication is the northwestern part of the sea, where the three largest rivers, the Danube, Dniester and
Dnieper are inflowing.
Increase in nutrients in the river discharge triggered the mass development of
phytoplankon and an expansion in the area of its blooms. This phenomenon has
been thoroughly studied by Ukrainian, Romanian and Bulgarian scientists. A large
algal biomass provides good feeding conditions for plant-eating animal plankton
(zooplankton) and a sharp increase in the numbers of some zooplankton species
occurred in the 1970s and 1980s.
Aquatic organisms, especially macroalgae, are widely used as bioindicators for
the study of marine Nuclides and heavy metals are the most harmful elemental
pollutants and are of particular concern because of their toxicities to humans. They
include both essential elements like iron and toxic metals like cadmium and
mercury. Most of them show significant affinity to sulphur and disrupt enzyme
function by forming bonds with sulphur groups in enzymes. Cadmium, copper, lead
and mercury ions bind to the cell membranes hindering the transport processes
through the cell wall. Some of the metalloids, elements on the borderline between
metals and nonmetals, are significant water pollutants (Manahan 1999).
Radionuclides occur naturally in the environment but recently some artificial
radionuclides have been introduced. In the past there have been several accidents, at
18 Radioecology of the Black Sea
297